[GreenKeys] Looking for HP Laserjet IIp+ power supply

[Charles]

Actually I just fixed it ;) <Emily Litella> Never Mind.

I took the supply all the way apart and found one secondary filter cap that 
had leaked electrolyte. Cleaned and fixed that, but still no luck. 155 volts 
on the main filter cap. Then I noticed that occasionally it would try to 
start for a blink but then the voltages would just drop to zero. So I 
started looking around the section that had to be for bootstrap power to the 
switching regulator, a common TL494 chip with datasheets online. Sure 
enough, a small electrolytic on the primary side had blown its bottom out. 
The diodes around it were still good. Changed that cap and a couple more 
suspicious looking small ones and the voltages came right up (including the 
24V once I pushed the cover-open microswitch).
Put it back in the printer, screwed it all together (a very modular design 
for easier field servicing) and fired it up. Test page printed perfectly. 
Saved some $ on a new laser printer. For now :)

I like these old cinder-block-sized (and weight) printers too. They last 
ALMOST forever...

Charles


-----Original Message----- 
From: Mike Stein
Sent: Wednesday, October 31, 2018 1:48 PM
To: Charles
Subject: Re: Looking for HP Laserjet IIp+ power supply

Got a picture?

----- Original Message ----- 
From: "Charles via cctalk" <cctalk at classiccmp.org>
To: "cctalk digest" <cctalk at classiccmp.org>
Sent: Tuesday, October 30, 2018 10:01 PM
Subject: Looking for HP Laserjet IIp+ power supply


> The main power supply for my ancient Laserjet IIp+ printer has given up.
> Fuse is not blown. Power switch has continuity... don't feel like trying 
> to
> debug and repair the "brick".
>
> There are two Sony labels: One says Model RG1-1782 (I think that's the HP
> part number) and the other Model CD-91A, 100-115V.
> Does anyone have a working one in their junkbox?
>
> This is the LAST time I repair it before it goes to the recycler! I think
> I've changed every module except this one.
> It has become my grandfather's axe: new head and new handle, but it's 
> still
> my grandfather's axe :)
>
> thanks
> Charles
>